The invention relates to an airbag module for an occupant restraint system of a motor vehicle, comprising a housing in which a folded inflatable airbag is accommodated.
An airbag module of the initially named kind is known and is intended to protect the vehicle occupants from injuries in accidents. For this purpose, the airbag is inflated during the accident within a few milliseconds and forms a cushion into which the passenger immerses during the sudden deceleration of the vehicle.
An object of the invention is to provide an airbag module for an occupant restraint system of a motor vehicle which can be cost-effectively manufactured and which helps to prevent injuries to occupants.
For satisfying this object, an airbag module with the features in accordance with the claims is proposed, in particular an airbag module in which a part of the housing is designed as a covering which is movable into the vehicle interior and which serves during the unfolding of the airbag for supporting the knees of the occupant, and in which the airbag is designed in such a manner that it can be unfolded through an opening at the housing past the covering and into the vehicle interior when the covering is at least partly moved into the vehicle interior. In one embodiment, the moveable covering is a flap which is pivotal about an angle of less than 45 degrees. In one embodiment, the movable covering is a flap which is pivotal about an angle of less than 45xc2x0.
In the invention, both the housing and the airbag fulfill a double function. On the one hand, the housing serves for the accommodation of the airbag. On the other hand, the covering of the housing, which is moved into the vehicle interior during an accident supports the knees of the occupant so that the latter is retained in his seat during an accident. The airbag which is unfolded and inflated past the covering and into the vehicle interior in turn supports the covering and presses the latter against the knees of the occupant. At the same time, the airbag prevents injuries to the upper torso and to the head of the occupant, who continues moving forward in the direction of travel during the sudden deceleration of the vehicle. Furthermore, by the use of said housing with said covering the construction of the airbag module is comparatively simple so that the manufacture of the airbag module in accordance with the invention is simpler in comparison with known airbag modules.
Thus, it is particularly advantageous when the covering is stiffened through additional stiffener elements. By this, the supporting forces which are exerted by the knees of the occupant on the covering during the accident are transmitted by the stiffened covering over a large area of the airbag, so that the pressure in the airbag acting to support the covering can be lower than if the corresponding supporting forces had to be taken up by the airbag in a point-like manner.
In a preferred further development of the invention a flap being pivotal into the vehicle interior is used as movable covering. The use of a flap as covering has on the one hand the advantage that the flap assumes a definite position relative to the housing during the unfolding of the airbag, whereby the unfolding of the airbag can be intentionally influenced when the flap is designed accordingly. On the other hand the forces which are exerted during the accident by the occupant on the flap are partially transmitted to the housing by the pivot points of the flap so that the airbag only needs to take up and to intercept a portion of the forces arising at the flap.
Furthermore, it is advantageous when the airbag is firmly connected to the inner side of the housing which faces the covering. By this, it is achieved that the airbag is supported via the housing at the body of the vehicle. Alternatively, it is possible to provide the airbag at an inner side of the covering.
In a further preferred embodiment of the invention the housing of the airbag module forms a pivotal lid of a glove compartment. In this way the airbag can be arranged space savingly in the vehicle interior. At the same time an additional lid for the glove compartment can be ceased.